brian - 11 hours ago »
grahamlthompson - 14 hours ago »
BBC1 HD isn't currently using 5.1 sound due to a fairly long standing issue with periodic audio drop outs.They were with the Eurovision Song Contest a few weeks ago.
Perhaps they got the audio from a different source.
See
http://www.a516digital.com/2014/01/bbc-investigates-sound-glitches-on-hd.html
The last blog from the BBC confirmed they still had issues.
